The TM120M designation means the thermal element is fixed at 100 A (the Iu rating), while the magnetic short-circuit pickup is adjustable between 700 A and 1600 A — that's 7x to 16x the rated current, giving you room to coordinate with downstream devices without nuisance tripping on motor inrush. Breaking capacity is the headline number here: 220 kA at 240 V AC, 154 kA at 415 V, and 121 kA at 440 V.
Thermal derating — what the temperature table tells you
Above that, the thermal element must be derated: 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C. If your panel internal ambient runs hot — say 60 °C near the top of a sealed enclosure — this breaker still carries 96 A continuous, but you lose 4 A of headroom.
The 76.2 mm width is a standard 3-pole MCCB footprint — it occupies three 25.4 mm (1-inch) module positions on a DIN rail or panel-mount base. Depth of 70 mm means it clears most shallow backpanels, but verify gland-plate clearance if the breaker is mounted near the enclosure rear wall.
What it does not include
No communication function, no phase failure detection, no ground-fault monitoring. The neutral conductor is not upgradeable or retrofittable. These are deliberate omissions — this is a plain thermal-magnetic MCCB for straightforward feeder or motor branch protection, not a smart breaker with metering or remote trip.